Primary Sources are original materials from the time period involved. They are generally just the information or artifact, and do not include evaluation or commentary.
Examples include:
Newspapers
Artifacts
Letters
Codes of Law
Speeches
Scientific Findings
Media (Photographs, Audio Recordings, etc.)
Government-Issued Documents
Art and Architecture
Fiction
Musical Scores
Maps
Secondary Sources
Secondary sources offer interpretation or commentary on primary sources. However, the definition of secondary sources may depend on the discipline or topic.
Examples include:
Commentaries, criticisms
Biographies
Critical Works
Documentaries
Reviews
Peer-Reviewed Journals
Magazine or Newspaper Articles
Tertiary Sources
Tertiary Sources condense primary and secondary sources.